What is the difference between DTPMPA and HEDP?

DTPMPA (diethylenetriaminepenta-methylphosphonic acid) and HEDP (hydroxyethylidene diphosphonic acid) differ in several aspects, and the following is a detailed analysis of the differences:

I. Basic properties

Second, the chemical structure and composition

• DTPMPA: is a compound containing multiple amino and phosphonic acid groups, with a complex molecular structure, which makes it able to form a variety of stable complexes in water, thus providing excellent scale and corrosion inhibition.
• HEDP: It is an organophosphonic acid compound with two phosphonic acid groups in its molecule, which can form stable complexes with metal ions (such as calcium ions) in water, thus playing the role of scale and corrosion inhibition.

Third, performance characteristics

1. Scale inhibition effect:

• DTPMPA has excellent performance in high temperature and alkaline environment, and its scale inhibition effect is especially significant for insoluble salts such as calcium carbonate.
• HEDP also has good scale inhibition effect, but compared to DTPMPA in some specific conditions of the scale inhibition effect may be more excellent.

Corrosion inhibition:

• Both have certain corrosion inhibition effect, but the specific effect may vary depending on the use of the environment and conditions.DTPMPA may show stronger corrosion inhibition ability in some cases, especially with manganese ions compound use.

High Temperature Resistance:

• DTPMPA maintains stable performance at high temperatures and is suitable for use in water systems requiring high temperature treatment.
• HEDP can also be used under certain high temperature conditions, but the specific high temperature resistance may be slightly inferior to DTPMPA.

Stability:

• Both DTPMPA and HEDP have a certain degree of stability and are not prone to decomposition or failure under light and heat conditions. However, HEDP can still maintain good stability under high pH value, while DTPMPA may appear in some extreme conditions of performance changes.

Application Areas

• DTPMPA: It is mainly used as scale and corrosion inhibitor for circulating cool water and boiler water system, especially in alkaline environment with excellent performance. In addition, it can be used in textile printing and dyeing, pigment dispersion, fertiliser and concrete additives.
• HEDP: It is widely used as scale and corrosion inhibitor in circulating cooling water system and medium and low pressure boiler in electric power, chemical industry, metallurgy, chemical fertiliser and other industries. In light textile industry, HEDP can be used as cleaning agent for metal and non-metal; in bleaching and dyeing industry, it can be used as peroxide stabilizer and colour-fixing agent; in cyanide-free plating industry, it can be used as complexing agent; in pharmaceutical industry, it can be used as carrying agent for radioactive elements.

In summary, DTPMPA and HEDP have obvious differences in chemical structure, performance characteristics and application areas. In practical application, suitable scale and corrosion inhibitors should be selected according to the specific use environment and conditions.

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